I don't see why they need a wall. Securing them to each other is a common practice here.

Thanks for the replies! bostonpam, I agree with eustacem, your kitchen is beautiful. And I can't see the difference in heights from the countertops to the top cabs. Did you have trouble getting your backsplash even? One of the things I'm worried about is once the backsplash comes around the corner to the window, it'll be different heights on either side. I'm thinking beadboard backsplash, so it'll have a vertical line, but it'll still have a horizontal trim piece at the top. dianlo, interesting idea. I don't think I have a straight wall, floor or ceiling in my house, so just making the difference smaller but not perfect might do the trick. My GC and DH might think I've moved to a new level of crazy to want to move the cabinets 1/2" though! :) buehl, I've seen your posts with your 3 piece crown molding before and I think it's brilliant! I think it might be a little tougher since we only have 2-1/2" crown to work with, the filler piece might be in danger of disappearing all together, but I know it'll come in handy with our crazy ceiling! marcydc, our GC had quite a time getting our base cabs level. I think we could nickname our kitchen Shims R Us!

As Livia mentioned, having cabinets go all the way to the ceiling is not recommended. Ceiling heights are rarely the same throughout the room and cabinets to the ceiling will highlight these issues - if they can even fit in all places! Instead, use a minimum of 2-piece molding with one piece "filler" (flat panel - no detail) that can be cut to fit and a piece for the top that is the same all around. We used 3-piece: . . The middle piece (Stock-S) is the "filler". Our ceiling height varied by an inch or so throughout the Kitchen. To handle this: Three pieces: -- Crown - top piece -- Stock-S - filler piece in the middle -- SoffitA - bottom piece The bottom piece ("SoffitA") was installed on top of the cabinets. It's the same size all over. The top piece ("Crown") was installed on top of the filler piece ("Stock-S") and is the same size all over. The middle filler piece ("Stock-S") was installed b/w the Crown & SoffitA. However, the height of the piece varies. It was cut to fit b/w the Crown and SoffitA to account for the varied ceiling height. The same can be done with two pieces - the equivalent of the "Crown" and "Stock-S" pieces. Doing this makes it look like the Kitchen's ceiling height is the same all over and makes the cabinets look customized for your space.

Thanks would love to hear from a professional kitchen designer on cost and feasibility. I have so many doubts that this would ever look like anything but a bad diy project